World TB Day: Global epidemic hits home

Every week, two new people on average are diagnosed with tuberculosis (TB) in King County. Many of these cases are investigated, treated and managed through our local TB program without public attention, but we’ve seen recent instances in schools (here and here) and a university, health care facilities (here and here), a group residence and jail that have generated interest and concern.

King County’s experience is the result of a continuing global epidemic that kills about two million people every year. A disease that’s largely treatable in the United States, TB rages in many parts of the world where health systems are not capable to respond.

In honor of this year’s World TB Day, March 24, Public Health Insider sat down with Katelynne Gardner Toren, MPH, an epidemiologist with our TB program, to learn about the latest developments in our fight against TB in King County and around the world.

If TB is treatable with antibiotics, why do people continue to die around the globe?

Many countries are not fortunate enough to have strong TB programs like we do in the United States. Here, local health departments like ours are able to identify new infectious cases through the health care system, and ensure that people get appropriate treatment and complete their medication course so they get well and don’t spread the disease to others.

We also are effective at finding and testing people who may have been exposed to people who are infectious, and offering treatment to those who contract latent (or dormant) TB infection so it doesn’t develop into infectious TB disease that can spread.

All of this work is time and resource-intensive for health departments and also requires a health care system where people are able to get care reliably.

Q: How is this global epidemic affecting us in King County?

In 2016, we saw a slight increase in the number of people diagnosed with TB disease, up to 101, from 98 the previous year. This still puts us at near-historic low rates of TB in King County, at 4.8 cases per 100,000 people.

Even so, as a region, we have higher rates of TB disease than for the state or the nation as a whole. That’s because we are at a global crossroads for trade and migration in King County, with many residents who previously lived in parts of the world where TB is much more common. 77 percent of the people with TB disease in King County were born outside of the United States.

Q: You mentioned dormant (or latent) TB infection. What is it, and why is it a concern?

Unlike infectious (or active) TB disease, latent TB infection can’t be passed from person-to-person, and people are not ill with the disease. Approximately 100,000 people in King County have latent TB infection. While they aren’t contagious now, they could potentially have active TB disease in the future and also infect others. Approximately one in 10 people with latent TB infection will develop active TB disease in their lifetime.

We have more people with latent TB infection than anywhere else in the state, and it presents an ongoing risk for TB outbreaks in our county. We need funding above what we receive now to work with community providers to find and treat all latent TB infection in our area. This would help to reduce new infectious TB cases and the risk of outbreaks.

Q: What is drug-resistant TB? Are we seeing it in King County?

When the TB bacteria in a person is resistant to at least one TB medication, it’s called drug resistant. If the two primary medications don’t work effectively against TB in a person, it’s considered multi-drug resistant, or MDR. In 2016, we had 16 cases who were resistant to at least one medication, and no new cases of MDR in King County. In 2017, we’ve already had two MDR cases. Globally, about five percent of TB cases are now MDR.

Drug resistant TB is a significant threat to our ability to control TB, because it reduces our options to treat people effectively. MDR cases are also much more expensive and take much longer to treat. Normal treatment is 6-9 months, but MDR cases can take 18-24 months. MDR treatment costs well over $100,000 per case, while standard treatment costs about $17,000.